Logic for mail sending when sponsor is no longer member
CHANGELOG:
### ADDED
- [#630](https://gitlab.com/coopdevs/odoo-somconnexio/-/merge_requests/630) Enviament de correu a les persones apadrinades per socis que es donen de baixa.
Related card: https://trello.com/c/rESyQCmI/974-enviament-de-correu-a-les-persones-apadrinades-per-socis-que-es-donen-de-baixa
Edited by Pelayo García